Aerodynamic and structural analysis for blades of a 15MW floating offshore wind turbine

Recent years have seen an important evolution toward large-scale and increased gross capability in the design of floating wind turbines. For an up-to-date 15 MW wind turbine, the slender blades sustain undesirable risks of failure and fatigue due to the significant interaction between fluid and structure (FSI). Considering its sufficient resolution, a one-way CFD-FEA (Computational Fluid Dynamics-Finite Element Analysis) FSI model is established on a full-scale floating IEA 15 MW Reference Wind Turbine (RWT). Particular attention is focused on the effects of the wave-induced motions on the wind field, the structural response of the blades, and the power generation performance of the floating 15 MW wind turbine. It is found that the relative velocities between the blade and the wind field are evidently disturbed by the pitch and surge motions, resulting in the amplified pressure maxima and abrupt change on the leading edge. Meanwhile, the motions amplify the maximum thrust, torque, and aerodynamic power, but also introduce the minima close to zero. This would lead to significant instability in energy production and possibly a sudden halt of the wind turbine gearbox. Moreover, owing to the detailed 3D composite FEA model, the enlarged stresses and tip deformations of blades due to the platform motions are revealed with better fidelity than the beam model in previous FSI simulations.